It is important in designing solid products obtained by molding powder food to give the solid products mechanical strength against shock applied thereto during production and shipping and disintegrating property and solubility in water or in the mouth. In other words, it is ideal for the sold products to be rapidly disintegrated and dissolved while maintaining necessary mechanical strength for various applications and improved convenience of the food product.
In order to improve the solubility of a solid food product, the solid product is small-sized and increased in surface area, additives are included in the food product, or the porosity is increased. When the product is small-sized, it has to be produced in a larger number, leading to increased production cost and difficulty in handling. When additives are included, the taste may be impaired. Furthermore, additives cannot be incorporated in formula milk powder. With regard to the adjustment of porosity, it is not always easy to ensure both the strength and the solubility in various food products.
The Japanese Laid-Open Patent Application Publication (before examination) No. H09-104619 (Patent Document 1 below) discloses a tablet having a recess. The tablet recess is a cleavage line to easily break the tablet. It is not particularly intended to improve the solubility.
The Japanese Laid-Open Patent Application Publication (before examination) No. H08-333236 (Patent Document 2 below) discloses a bath agent having a recess nearly in the form of an inverted truncated cone with a convex curved inner wall. However, the bath agent is not a food product. Furthermore, this bath agent has only one recess in the center of the surface.
Milk powder is a food product having storage stability improved by removing from milk most of the moisture necessary for microorganisms to grow. With the moisture being removed, the milk powder is reduced in volume and weight and is easily transported. Milk powder is highly advantageous in storage stability and transportation. Milk powder is easily dissolved in heated water. However, milk powder has to be measured to an appropriate amount each time it is dissolved in heated water. Milk powder may be scattered when it is measured or removed from a container. So, solid milk formed by solidifying milk powder has been proposed (the Japanese Laid-Open Utility Model Application Publication (before examination) No. S49-130189 (Patent Document 3 below) and Japanese Laid-Open Utility Model Application Publication (before examination) No. S61-118280 (Patent Document 4 below)). However, in practice, it was not to solidify milk powder while ensuring both strength and solubility. Solidified milk powder is easily disintegrated and difficult to handle. Furthermore, solid milk has a smaller surface area and therefore is difficult to dissolve in heated water when compared to milk powder. Therefore, solid milk having a high level of solubility and a specific level of strength is desired.
The Japanese Laid-Open Patent Application Publication (after examination) No. S49-4948 (Patent Document 5 below) discloses “a granulated milk powder.” It is recited that “the granulated milk powder has porous inner texture so that it allows water to easily infiltrate and, therefore, is easily disintegrated, dispersed, and dissolved when introduced in heated water.” However, “the granulated milk powder” in this publication is a mixture with sugar or glucose and suitably “added to coffee or tea.” In other words, it is not made of milk powder only or given to babies instead of breast milk.